|
Featured
Topics
Lively
Essays
on Topics of Special Interest:
Structure
& Function, Genetics, Behavior, Ecology, etc.
For
Selected Species or Groups or For Life in General
Future
Features
Current
Feature
Past
Features
Future
Features
Leapin' Lizards!
The Evolution of Birds
The Amazzzing Honey Bee
It's a Small World:
Biomes We Share (And Some We Don't)
Genetic
Engineering: DNA Sequences & Real World Consequences
A Dog's Life
Other Worlds...Deep Under
the Sea
If...: The
Possibilities of Extra-Terrestrial Life
You've Got Some Nerve!
The Forest Primeval
From Cradle to Grave
Nature or Nurture?
Return
to Top
Current
Feature
HUMMINGBIRDS:
SMALL
SIZE, BIG ATTITUDE!
By
Douglas Drenkow
One
of the greatest joys in life for my dear old dad, our visitors, and me is
watching the steady stream of hummingbirds that visit the feeder just
outside our living room window.
Not
that it's a love-fest -- nothing's more anti-social and belligerent
than a hummingbird! Like
similarly tiny and ill-tempered shrews, hummingbirds lose body heat so
quickly that their metabolism must burn food like an SUV burns gas.
About the only thing that beats nearly as fast as a hummingbird's
wings (typically 50 beats a second) is its heart (up to 20 beats a
second). To claim enough territory, these little birds have to have an
attitude as big as their appetite.
Our
neighborhood hummingbirds keep us quite busy, particularly during the
spring and summer, cleaning and re-stocking their feeder, with one part
sugar to three or four parts water: No
low-carb diet for them! And
no need for food color -- in fact, some say it's best not to add it -- particularly if the feeder is red (seen well by birds but poorly by bees).
As
much as we'd like to think ourselves and our syrup-dispensers
indispensable, hummers in much of the country can do quite nicely without
us: They get the bulk of
their calories from the nectar of flowers and all of their protein from
pollen and bugs. Pollinating
flowers and exterminating pests, most hummingbirds are as beneficial as
they are beautiful.
Although
many young and female hummers are drab, most adult males are colorful,
showing off when defending their territories (in usually harmless "sword
fights" of bills midair) or when attracting their mates, as with
elaborate dances (Our local males do a lot a "singing" as well -- they sound something like melodic cicadas).
The colors of hummingbirds are typically produced by iridescent
feathers -- sometimes changing colors as they catch sunlight from
different angles -- as on ruby-throated hummingbirds, probably the most
common in North America.
With
over 300 species, hummingbirds compose the second-largest family of birds
in the New World. Not native
elsewhere, hummingbirds have inspired many legends amongst Native
Americans, since the days of the Maya.
Hummingbirds typically represent life-giving spirits, as of rain,
or even the souls of warriors lost in battle and returning to their loves.
Have
you ever seen a striped hummingbird with antennae?
That's actually a hummingbird moth, whose caterpillars are
hornworms -- like those little buggers that feast upon my tomato plants. One year we bought some of those papier-mache-like egg
cases of praying mantids at a garden shop and put them out in the tomato
patch -- we didn't have problems with hornworms that year.
But our hummingbirds weren't too keen on the idea.
At the end of the season, one of the six-inch mantids crawled up on
the feeder; and when a hummer approached, the big bad bug leaped out and
latched onto the neck of the bird! With
eyes almost as big as mine, the hummer used its remarkable powers of
flight (which would put a helicopter to shame) to immediately reverse
direction, stop abruptly, and then fly off at literally a mile a minute,
leaving the mantid momentarily in midair -- like Wile E. Coyote -- before crashing to the ground. The
traumatized bird eventually returned to feed, but only after scolding us
in the "peanut gallery" ever so roundly and soundly!
Speaking
of hitching a ride, there's an old legend (started by maybe none other
than James Audubon) that says that hummingbirds ride atop geese.
Not true, although many species of hummers do rack up thousands of
frequent flier miles each year with their migrations, as down to Central
America.
Back
in their northern range during the spring, hummingbirds mate, the female
then laying typically two jellybean-sized eggs in a walnut-shell-sized
nest and doing all of the work of feeding and rearing the young...while
the males are out drinking and raising a ruckus.
And
here I thought we humans were the only birdbrains on Earth!
======================================================
To
see and read more about hummingbirds, visit hummingbirds.net,
hummingbirdworld.com,
and montereybay.com/creagrus.
To see and read more about The World of Life, please visit
DouglasDrenkow.com/Life.
Return
to Top
Past
Features
WELCOME
TO "THE WORLD OF LIFE"!
By
Douglas Drenkow
"One
touch of nature makes the whole world kin." --
Shakespeare
Welcome
to "The World of Life", a weekly look at the wondrous diversity of
life on Earth -- from the lowliest worms and ferns to grandest redwoods
and whales and everything in between (including you and me).
We will explore the amazing ways in which life has adapted to
virtually every habitat on land, under water, and in the air; and we will
discover the marvelous ways in which life works, from the intricacies of
genes and the vital functions of vital structures, to the delicate balance
of ecosystems. The more we
understand about plants, animals, and other "creeping creatures having
life" the more we understand about ourselves.
"So,"
you may ask, "what is life?"
Well,
my philosophical friend, let's take a look at two living creatures and
see what, if anything, they have in common.
Consider a bacterium and (for want of a better subject) me!
Both
the germ and your humble human are composed of living cells.
The bacterium consists of just a single cell, its biochemical soup
sealed off from the environment by a membranous envelope, within a rigid
cell wall. I, by contrast, am
made-up of trillions of individual cells, each also bound by a membrane
but not enclosed within a cell wall (We of the animal persuasion tend to
be rather "flexible"). Each
of my cells is alive in its own right, carrying the genetic blueprint to
reproduce all the rest of me (as if one of me weren't more than enough).
My DNA, unlike that of the bacterium, is housed within a
membrane-bound "nucleus"; in fact, many of the functions inside my
cells are performed within membrane-bound "organelles" -- just like
many of the functions of my body are carried out by tissues (specialized
groups of cells), in organs (specialized groups of tissues), in organ
systems (specialized groups of, well, you know).
Long before the Industrial Revolution, nature devised an efficient "division of labor". Works
for me!
The
bacteria and I both exchange certain materials and forms of energy with
the environment. Concerning
what gets in and out, the membrane of a living cell is as selective as the
Marine guard at the White House door (Semper fi!).
Like higher plants, many bacteria convert light-energy from the sun
into chemical energy in foods. Some
bacteria convert chemical energy from minerals into chemical energy in
foods. But you and I, as
animals in good standing, don't bother to make our own foods:
We simply consume other creatures to acquire the energy and
materials we need. Plants, I
suppose, could get along quite well without us hungry critters; but we do
have our uses -- worms recycle wastes, bees pollinate flowers, and I
water my garden (and occasionally talk to my turnips).
Both
the bacterium and I can (at least theoretically) produce offspring,
although a bacterium reproduces by "fission" (simply splitting in two)
whereas I must find a mate (a number of candidates for which have told me
to split).
Finally,
the bacterium and I will eventually die (even if we watch our cholesterol
and exercise regularly). Although
I will probably outlive the bacterium's great-, great-, great-...(you
get the picture) grandchildren, all those generations give the bacteria
the opportunity to develop enough variations, even by chance mutations, to
evolve far more in my lifetime than humankind has over millions of years: We may be "advanced", but the bacteria are hardly "primitive".
Life
is a process -- of birth, growth, reproduction, and death -- consuming and producing materials and energy and transforming the world in
ways that even the most complex non-living systems (the atom, the weather,
the largest galaxies in the universe) cannot.
In
the weeks ahead, I hope you will join me in a voyage of discovery, as we
explore the incredible variety and amazing ways of The World of Life!
"And
God saw every thing that He had made, and behold, it was very good." -- Genesis 1:31
======================================================
To
see and read more of "The World of Life" -- including a wealth of
scientific information and links to fascinating photos -- please visit my
website, DouglasDrenkow.com/Life.
Return to
Top
|
